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When to Plant Thyme in Jefferson County, PA

Jefferson County, Pennsylvania Zone 6a May

This month in Jefferson County, Pennsylvania

Each item below is timed to Jefferson County, Pennsylvania's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 18
Avg. first frost October 7
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out thyme

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.

Jefferson County, Pennsylvania is in USDA Zone 6a. The average last spring frost is May 18 and the first fall frost is October 7, giving you a growing season of approximately 142 days.

At an elevation of 1,026 feet, Jefferson County receives approximately 42.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Thyme to ensure they mature before fall.

Jefferson County, PA (Zone 6a) Short season
142 days
Last Spring Frost May 18
142 growing days
First Fall Frost October 7

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Transplant: May 16 🍅 Harvest: Jul 25 – Sep 26
Recommended (50%) ✓ Fits season (2 days to spare)
Transplant: May 25 🍅 Harvest: Aug 3 – Oct 5
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: Jun 8 🍅 Harvest: Aug 17 – Oct 19

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Jefferson County

How your county's soil matches Thyme's growing requirements.

Soil pH

Your soil pH (4.8–6.4) is more acidic than Thyme prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Jefferson County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.0%) — Thyme will thrive.

How to Plant Thyme

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Thyme

2
successive plantings in your 142-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Thyme

Thyme needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Thyme Needs Rainfall You Supplement Action
Jan 2.5" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 1.3" 4.1" 0" ✅ Rainfall sufficient
Jun 1.3" 4.3" 0" ✅ Rainfall sufficient
Jul 1.3" 4.7" 0" ✅ Rainfall sufficient
Aug 1.3" 3.8" 0" ✅ Rainfall sufficient
Sep 1.3" 3.2" 0" ✅ Rainfall sufficient
Oct 1.3" 3.2" 0" ✅ Rainfall sufficient
Nov 3.4" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Thyme Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Thyme needs ~980 GDD — county provides 1,739 GDD Excellent fit

Thyme Planting Timeline — Jefferson County, PA

Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 25 May 25 – Jun 8
Harvest August 3 Aug 3 – Oct 5

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

142 days in Jefferson County

Growing Tips for Thyme in Jefferson County

Direct sow Thyme outdoors after May 18 in Jefferson County when soil has warmed and frost danger has passed.

General growing tips

Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thyme in Jefferson County, PA?

Jefferson County is in Zone 6a with an average last frost of May 18. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, PA?

Jefferson County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is May 18 and first fall frost is October 7.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Jefferson County, PA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.